We recently added "resizableWithParent". Yet, in the following case, when the scroll pane first comes up it equally distributes the width among both children in the split pane.

       <SplitPane>
            <ScrollPane prefWidth="250" id="left-pane">
                <SplitPane.resizableWithParent>false</SplitPane.resizableWithParent>
            </ScrollPane>
            <ScrollPane></ScrollPane>
        </SplitPane>

So the idea here is that I have one side which is not supposed to resize with the parent, and the right size is. Now I want to have the left size assume its preferred size. However this doesn't work, both ScrollPanes get 1/2 of the available space, I have to do a setDividersPosition call. I don't think I can do that in FXML without resorting to scripting.